WECOWBS02
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
We report on negative electron affinity (NEA) of GaAs using robust layers based on the use of Cs, Sb and Oxygen. A detailed parametric study has been performed on the growth conditions and using the equivalent Sb thickness as main parameter. Our results confirm that dark lifetime (measured as 1/e decay of the quantum efficiency as function of time) of the GaAs activated using this method is improved by a factor 10. More importantly the operating lifetime (measured as 1/e decay of the quantum efficiency as function of the extracted charge) is improved by a factor 40 with respect to Cs-O activated GaAs operated under similar conditions. Such improvements on the lifetime are achieved at expenses of a slightly reduced QE and electron spin polarization.
